Competition of altcoin is present and really does affect some coins. Only those who have a real project will survive in the market. But, for ethereum I think it will develop more in the future.
Altcoin's future depends on bitcoin future. It is undeniable correlation between them. Most of waves, bitcoin and altcoins move in opposite directions. Bitcoin moves upwards, altcoins move downwards, and vice versa. However, in the long term, with potential growth of blockchain technology, I think both bitcoin and altcoin will rise in value.